Process of preparing ptjlp having wax-impregnated fibers



Drawing.

um'rso sures PATEN 'r canes.

MK B. -DAVIDSON, 0;! MAIBSEIILES, ILLINOIS, ASSIGNOR T0 NATIONAL BISCUIT COMPANY, OF NEW YORK, If. Y., A CORPORATION OF NEW JERSEY.

PROCESS OF PREPARING PULP HAVING wAX-IMPBENATED FIBERS.

To all whom it may concern:

Be it known that I, FRANK B. DAVIDSON, a citizen of the 'United States, residing at Marseilles in the county of La Salle and State of Illinois, have invented new and vuseful Improvements in Processes of Prearing Pulp Havin Wax-Impregnated F irs, of which the Iollowing is a specification.

This invention relates to a process where by the waste or scraps of waxed papers or waxed box-boards, such as scraps of wax saturated papers and scraps of wax coated apers and box-boards and the like, which lieretofore have had little or no value as material for paper making by the practice heretofore employed because of the presence of wax therein, may hen-sad for preparing pulp for paper making and permit the production of a paper sheet or web which in the initial makin thereof may .have one or more-or all 0 its plies-formed of wax impregnated fibers, so that the article or prodnot made from a web or webs so formed may be rendered moisture and water resistant.

It has been the practice heretofore, in making waxed papers and waxed box-boards and the like, to ap 1y thewax after the pa er or box-board as been made from a pu p free from wax, as by either forcing the wax into the paper sheet fromthe outside thereof, or by applying a coating or layer of wax on the outside of the same.

In applying wax in the manner first while in the second it ismerely coated.

Papers saturated with wax are generally used to, make bread wrappers, liners, drinking cups, and the like, where a thin stock is required, while papers coated with wax are usually heavier or thicker and aroused for making'flcartons, boxes,- and other receptacles for containing butter, baker prodnets and edibles, or any merchan ise required. to be packed in moisture proof packages, No matter which of the two meth- Speolfloation of Letters Patent.

Application filed April 21,

Patented June 29, 1920.

1919. Serial No. 291,054.

sis

eliminating the necessity for the subsequent application of wax to the sheet to obtain moisture or water resistant qualities and producing similar results, at much less ex pense.

In carryinfg' out my novel process, I take a quantity 0 scraps or waste of the heavily coated or saturated waxed papers and mix them with a quantity of scraps or waste of the waxed papers carrying a lighter proportion of wax, the mixture being in such proportion to insure having enough waxed fibers in it to impregnate with waxall of the fibers present therein. The mixture is then. introduced or placed into the cooking chamber of a cooking'apparatus, preferably a rotary cooker, with ust enough water being added to reach all of the individual parts of the mass. The 0 enings to the cooker are then closed and t e mass cooked and revolved for a desired length of time, say about five or six hours, under a steam pressure of about thirty to forty pounds to the square inch. The steam is then shut oil and the cooker revolved forian' additional length of time, for about one or two hours, while the pressure is falling. During the cooking operation the action of the heat, moisture, and pressure softens the fibers and the wax and'cauaes the surplus wax liberated from the mixture and the waxed fibers to be forced into'the' unwaxed, fibers, the agitation in arted to the mass during the rotation oft e cooker servin to loosen up and separate the fibers all of them will be reached to be impregtion has been completed, the cooked mass is removed from he cooker, there being practically no waste or free water to carry away any part of the wax because the mixture was ]prepared initiall in such pro portions t at the unwaxe fibers of the mixture would carry what wax would be liberated from the heavily waxedfibers, with the result that there 'is practically no wax.after the cookingoperdtion has and insure that completed. Then follows the usual and well known method of reduction of the cooked mass into pulp and the conversion of the latter into paper or paper-board. By the process described, papers which are heavily waxed havc'fin? surplus wax liberated by the heat applied during the cooking opera tion and ful't'l'tl into the softened unwaxed fibers, thereby gaining a mass all of the fibers of which will he impregnated with wax. if the supply of waste waxed papers on hand is of that kind that are saturated or so heavily coated with wax that there is a surplus of that material, i may add to such papers srraps of unwaxed papers so as to present enough unwaxed fibers to rarry the surplus wax liberated from the waxed papers being used and obtain a mass all the fibers of which will be impregnated with wax.

in my copending application, fierial No. 291,655, filed April 21st 1919, l have described the manner of making a paper sheet or web having one or more or all of its plies made from pulp having wax impregnated fibers as produced by the prom ess described herein, so that the sheet well as the box board may have at least one of its lies made entirely of wax ini pre mated bers.

\hile I have mentioned herein a rotary rooker as the hform of cooking apparatus used in carryhg out my process, yet it is to be of course understood that any other type of cooking apparatus may be employed provided that steam pressure and agitation may be. applied to the muse during the rooking operation. Furthermore, in speaking of waxed papers, I means to include all of such papers which are treated with a material in the nature of wax for giving the paper or paperboard moisture and water proof qualities.

I claim as my invention:

1. The process of preparing pulp having wax impregnated fibers, consisting in mix ing together papers having wax d undamwaxed portions so as to have enough waxed fibers to impre note with the wax liberated from the waxe portions of the papers sulh stantially all the unwaxed fibers that may be present in the mixture, adring enough water to reach alt parts of the nlixture ainl cooking and agitatin the mixture under steam pressure to so ten the fibers of the ing together heavily coated or saturated waxed papers with those carrying a lighter proportion of the wax so as to have enough waxed fibers to impregnate with the wax liberated from the waxed portions of the papers substantially all the unwaxed fibers 5 that may be present in the mixture, adding enough water to reach all parts of the mix-- ture, and cooking; and agitating the mixture under steam pressure to soften the fibers of the papers and the wax and cause the latter to ie forced into the fibers of the papers.

{3. The proress of preparing pulp having:

wax impregnated fibers, consisting in mixing togetherenough heavily coated or saturated waxed papers with those carrying a lighter proportion of the wax to have enough waxed fibers to impregnate with the wax liberated from the waxed portions of the in )ers substantiall all the unwaxed so fibers tlat may be present in the mixture, adding enough water to reach all parts of the mixtigre, and rooking and agitating the mixture in a rotary cooker under a steam pressure of approximately thirty or forty pounds to the square inch.

4. The process of preparing pulp having wax impregnated fibers, consisting in mixing together enough heavily coated or saturated waxed papers with those carr a lighter proportion of the wax to lure enough waxed fibers to impregnate with the wax liberated from the other portions of the papers substantially all the unwaxed fibers that may be present in the mixture,

adding enough water to reach all parts of the mixture, vooking the mixture in a rotary cooker under a steam pressure of approximately thirty to forty pounds to the stpiare inch for a predetermined period 0 Unit" and then shutting oil' the steam and rmolving the cooker for an additional predetermined period of time while the pressure is falling, so as to soften the fibers and the wax into the fibers of the papers.

in testimony that l rlaimthe foregoing as my invention l ulli'x my signiiture this lHth (lay ol' April, lli llllll.

FRANK ll. DAVlDSUN.

'ing 90 and muse the latter to be formed 

